Field
Various communication systems may benefit from managing signal interference. For example, certain wireless communication systems may benefit from a dynamic time division duplex system involving slot allocation.
Description of the Related Art
Time division duplex (TDD) refers to duplex communication links in which different time slots, also known as subframes, in the same frequency band are dedicated to either uplink (UL) or downlink (DL) transmissions. In some embodiments, special subframes may also be included in the TDD frame. TDD allow for the asymmetric flow of uplink and downlink data transmissions. As the amount of uplink data in the network increases, more time slots in the radio frame can be dedicated to uplink transmission. On the other hand as the downlink traffic load becomes lighter, the amount of slots allocated to downlink transmission may increase.
Dynamic time division duplex (DTDD) systems are superior at adapting DL/UL radio resources slots to the time and spatially-varying short-term traffic demand observed in the network. This increased flexibility in resource assignment, however, can lead to a significant increase in interference. Inference can be directly caused by a power imbalance between the DL and UL transmission powers. Interference can be especially pronounced during UL transmission slots if a neighboring network node is undergoing a DL transmission.
FIG. 1 illustrates a radio frame allocation. In this diagram, interference between a first access point (AP1) 110 and a second access point (AP2) 120 is illustrated. AP1 110 can be allocated with a higher number of DL slots than AP2, which causes interference in certain UL slots of AP2.
FIG. 2 illustrates current network architecture under the 3rd Generation Partnership Project (3GPP). As can be seen in FIG. 2, current long term evolution (LTE) systems support dynamic TDD operation, but support only a fixed number of DL/UL slot patterns. FIG. 2 only lists seven possible UL/DL configurations. This is mainly due to the requirement to support legacy TDE-LTE devices. The supported DL/UL slot patterns within the radio frame in the current network architecture are therefore limited and heavily constrained.